A-A+
According to paragraph 2 how did birds adapt
问题详情
According to paragraph 2, how did birds adapt to achieve efficient flight？
A．They developed a skeleton with fewer bones.
B．Their organs became smaller over time.
C．Most of their weight was distributed in their heads.
D．Teeth were replaced by a beak made of keratin.请帮忙给出正确答案和分析，谢谢！
参考答案
正确答案：D
解析：... birds are toothless, an adaptation that trims the weight of the head... The bird's beak, made of keratin, has proven to be very adaptable." Choice A is not correct because the skeleton is honeycombed, which makes it strong and light, but it does not have fewer bones. Choice B is not correct because the organs are fewer, not smaller. Choice C is not correct because the head is lighter, not heavier.
